The dichotic lead effect of CV syllables in sensorineural hearing loss.

This study investigated central processing of dichotic CV syllables on 10 patients with sensorineural hearing losses. Porter's Dichotic Lag Index (DLI) was established for each S at asynchronies of alignment of 30, 60, 90, and 150 msec by presenting the lagging syllable first to the R and then to the L ear. Ss were required to record a response to both CV syllables. Patients exhibited a dichotic lead advantage while 10 normal-hearing control Ss exhibited a dichotic lag advantage. A R ear advantage was not abolished when the lagging syllable was presented to the L ear and was not enhanced when the lagging syllable was presented to the R ear. The lead advantage of the patients may be attributed to the distortion of acoustic encoding for speech, causing a reduction in the special processing requirements of CV syllables. The reduction in special processing may then be responsible for the shift in temporal advantage.